1. Field of the Disclosure
The disclosure relates in general to an organic light-emitting diode (OLED) structure, and more particularly to a top-emission OLED structure.
2. Description of the Related Art
As technologies progress, an organic light emitting diode (OLED) has become one of the most potential future lighting source. In the OLED, an emissive layer is sandwiched between two electrodes. At least one of the electrodes is partially light transmissive. These electrodes are referred to as an anode and a cathode. When the anode is connected to the positive terminal of a voltage source and the cathode is connected to the negative terminal, holes are injected from the anode into the emissive layer, and electrons are injected from the cathode. Combination of holes and electrons within the emissive layer results in emission of light.
Alternatively, in accordance with the luminescent path, OLED is classified into a bottom-emission OLED and a top-emission OLED. In a top-emission OLED, the electrode located at the top side is transparent and a reflective layer is located at the bottom side of the OLED, such that some of the light can pass through the electrode at the top side of the OLED and some of the light emitted to the bottom side can be reflected toward the top side. The reflectance of the reflective layer will affect the emission efficiency, as well as the power consumption.
In the OLED, the electric path is connected form the positive terminal to the negative terminal, and several layers are located on the electric path. The resistance of the layers will affect the power efficiency, as well as the emission efficiency. Accordingly, how to develop an OLED having low power consumption and high emission efficiency is a prominent goal for the industries.